Surface area coefficients for airship envelopes
A 1922 NASA technical report chart plotting surface area coefficients for airship envelopes, a technical record for engineers rather than a book written for general readers. The single picture is a scatter plot with a fitted straight line, with prismatic coefficient on the horizontal axis and surface coefficient on the vertical. A designer might take its clean grid, sparse cross markers and plain diagonal trend line as a model for minimal technical data graphics.
